Melatonin levels start to rise in your body when it is dark outside, signaling to your body that it is time to sleep ().

It also binds to receptors in the body and can help you relax. For instance, melatonin binds to receptors in the brain to help reduce nerve activity. In the eyes, it can help reduce dopamine levels, a hormone that helps you stay awake (, , ).

Although the exact way melatonin helps you fall asleep is unclear, research suggests these processes can help you fall asleep.

Conversely, light suppresses melatonin production. This is one way that your body knows it is time to wake up ().

As melatonin helps your body prepare for sleep, people who don’t make enough of it at night can struggle to fall asleep.

There are many factors that may cause low levels at night. Stress, smoking, exposure to too much light at night (including blue light), not getting enough natural light during the day, shift work and aging all affect melatonin production (, , , ).

Evidence shows that taking melatonin before bed can help you get to sleep (, , , ).

In an analysis of 19 studies on people with sleep disorders, scientists found that melatonin helped reduce the time it took to fall asleep by an average of 7 minutes.

In many of these studies, people also reported significantly better quality of sleep ().

Additionally, melatonin can help with jet lag, a temporary sleep disorder.

Jet lag occurs when your body’s internal clock is out of sync with the new time zone. Shift workers may also experience jet lag symptoms since they work during a time normally saved for sleep ().

Melatonin can help reduce jet lag by syncing your internal clock with the time change ().

For instance, an analysis of 10 studies explored the effects of melatonin in people who traveled through five or more time zones. Scientists found that melatonin was remarkably effective at reducing the effects of jet lag.

The analysis also found that both lower doses (0.5 mg) and higher doses (5 mg) were equally effective at reducing jet lag ().

Summary: Evidence shows that melatonin can help you fall asleep faster. In addition, it can help people with jet lag get to sleep.

May easy eat hand Eye Health

Healthy melatonin levels may support eye health.

It has powerful antioxidant benefits that could help lower the risk of eye diseases, such as age-related macular degeneration (AMD) ().

In one study, scientists asked 100 people with AMD to take 3 mg of melatonin over 6 to 24 months. Taking melatonin daily helped protect the retinas and delay damage from AMD, without any significant side effects ().

May Help Treat Stomach Ulcers and Heartburn

The antioxidant properties of melatonin may help treat stomach ulcers and alleviate heartburn (, , ).

A study with 21 participants found that taking melatonin and tryptophan along with omeprazole — a common medication for acid reflux — helped heal stomach ulcers caused by the bacteria H. pylori faster ().

In another study, 36 people with gastroesophageal reflux disease (GERD) were given either melatonin, omeprazole (a medicine that helps treat GERD) or a combination of both to treat GERD and its symptoms.

Melatonin helped reduce heartburn and was even more effective when combined with omeprazole ().

However, this area of research is fairly new. Future studies will help clarify how effective melatonin is in treating stomach ulcers and heartburn.

May Reduce Symptoms of Tinnitus

Tinnitus is a condition characterized by a constant ringing in the ears. It is often worse when there is less background noise, such as when you’re trying to fall asleep.

Interestingly, taking melatonin may help reduce symptoms of tinnitus and help you get to sleep (, , ).

In one study, 61 adults with tinnitus took 3 mg of melatonin before bed for 30 days. It helped reduce the effects of tinnitus and significantly improved sleep quality ().

May Help Increase Growth Hormone Levels in Men

Human growth hormone is naturally released during sleep. In healthy young men, taking melatonin may help increase growth hormone levels.

Studies have shown that melatonin can make the pituitary gland, the organ that releases growth hormone, more sensitive to the hormone that releases growth hormone (, ).

Current evidence suggests that melatonin supplements are safe, non-toxic and not addictive ().

That being said, some people may experience mild side effects, such as sleepiness, dizziness, headaches and nausea.

Melatonin may also interact with a variety of medications. These include blood thinners, blood pressure medication and antidepressants (, , ).

If you take any of the above, it’s best to check with your doctor before beginning a supplement.

There is also some concern that taking too much melatonin will stop your body from making it naturally. However, several studies have found that taking melatonin won’t affect your body’s ability to make it on its own (, , ).

Summary: Current studies show that melatonin is safe, non-toxic and not addictive. However, it may interact with blood thinners, blood pressure medications and antidepressants.